This disclosure relates generally to equipment utilized and operations performed in conjunction with a subterranean well and, in an example described below, more particularly provides for mitigating leaks in production tubulars.
Most countries have regulations which prescribe safety measures to be implemented when producing oil or gas (hydrocarbons). These regulations typically require that two barriers are to be provided between the environment and the produced hydrocarbons so that, if one barrier should fail, the other barrier will still prevent release of the hydrocarbons to the environment.
A first barrier is typically provided at the surface in the form of a valve. The second barrier is usually a production packer which seals off an annular space between a production tubing and casing which lines a wellbore.
Typically, the produced hydrocarbons enter the lower end of a production tubing and flow to the surface. A production packer seals off an annulus between the production tubing and the casing.
However, if a leak should develop in the production tubing above the packer (due to, for example, a faulty tubing connection, erosion, corrosion, etc.), then the hydrocarbons can travel to the surface via the annulus. In that situation, only a barrier at the surface (such as a casing valve) will prevent escape of the hydrocarbons to the environment, in violation of safety regulations.
In the past, this situation has been remedied by retrieving the tubing to the surface for repair or replacement (which is very costly and time-consuming), by patching the tubing to stop the leak, or by injecting a hardenable substance into the annulus above the leak to form an annular barrier. There are significant downsides to each of these prior methods.
Therefore, it will be appreciated that improvements are needed in the art of mitigating leaks in production tubulars.